A wide variety of systems have been in use as a variable optical device. One among them is an insertion-type variable optical device in which an optical characteristic of an incident light that passes through an optical path is changed by moving a single optical element, or a plurality of optical elements, in and out of the optical path with the help of an electromagnetic driving source or some other driving source. The functions of such an insertion-type variable optical device can be expanded by increasing the number of optical elements. With the recent development in an image quality of compact imaging equipments with a camera function, such as mobile equipments, micro-videoscopes, digital cameras, and endoscopic instruments, the shift in demand from a fixed-focus lens, a fixed-aperture diaphragm, and a fixed-characteristic filter to a variable-focus lens, a variable diaphragm, and a variable characteristic filter has been growing in the optical elements such as lenses, diaphragms, and optical filters. As an optical device to be applied to such compact imaging equipments, the above-described insertion-type variable optical device is drawing attention because of its simple structure. As an example of the insertion-type variable optical device suitable for downsizing, Japanese Patent Application Laid-open No. 2006-330314 discloses an optical device including a plurality of light shielding members each controlling an amount of light, a plurality of driving units respectively driving the light shielding members with an electromagnetic driving force from an electromagnetic circuit, and a base member for mounting the light shielding members and the driving units. In this optical device, downsizing the device while achieving stable driving is realized with a blocking member that blocks an inflow of a leakage flux in a mid portion of the driving units.